/Engine/Source/Runtime/Engine/Public/WorldPartition/WorldPartitionStreamingSource.h
Returns a box encapsulating all shapes.
FBox CalcBounds ( float InGridLoadingRange, [FName](API\Runtime\Core\UObject\FName) InGridName, const [FSoftObjectPath](API\Runtime\CoreUObject\UObject\FSoftObjectPath) & InGridHLODLayer, bool bCalcIn2D ) const